Emacs users: feedback on diffs between python-mode.el and python.el?

Rob Wolfe rw at smsnet.pl
Fri Oct 17 22:04:27 CEST 2008


Alberto Griggio <alberto.griggio at gmail.com> writes:

> Hello,
>
>> I second Bruno's points, the older python-mode.el is much
>> better, 
>
> I agree too. I can't really say what's missing from python.el, but I'm
> much more comfortable with python-mode.el. The triple-quote highlight is
> better in python.el, but I was successful in porting it to
> python-mode.el as well. Unfortunately, I don't have a clean diff, as I
> did some other tweaks...

Many thanks for this suggestion.
Now python-mode.el works like a charm. So many years of frustration. ;-)

I just downloaded python-mode.el from svn:
http://svn.sourceforge.net/viewvc/python-mode/trunk/python-mode/

and applied this patch (code taken from python.el):

--- python-mode.el.org	2008-10-17 21:20:29.000000000 +0200
+++ python-mode.el	2008-10-17 21:23:13.000000000 +0200
@@ -500,6 +500,63 @@
      '("XXX\\|TODO\\|FIXME" 0 py-XXX-tag-face t)
      ))
   "Additional expressions to highlight in Python mode.")
+
+(defconst python-font-lock-syntactic-keywords
+  ;; Make outer chars of matching triple-quote sequences into generic
+  ;; string delimiters.  Fixme: Is there a better way?
+  `((,(rx (or line-start buffer-start
+	      (not (syntax escape)))	; avoid escaped leading quote
+	  (group (optional (any "uUrR"))) ; prefix gets syntax property
+	  (optional (any "rR"))		  ; possible second prefix
+	  (group (syntax string-quote))   ; maybe gets property
+	  (backref 2)			  ; per first quote
+	  (group (backref 2)))		  ; maybe gets property
+     (1 (python-quote-syntax 1))
+     (2 (python-quote-syntax 2))
+     (3 (python-quote-syntax 3)))))
+
+(defun python-quote-syntax (n)
+  "Put `syntax-table' property correctly on triple quote.
+Used for syntactic keywords.  N is the match number (1, 2 or 3)."
+  ;; Given a triple quote, we have to check the context to know
+  ;; whether this is an opening or closing triple or whether it's
+  ;; quoted anyhow, and should be ignored.  (For that we need to do
+  ;; the same job as `syntax-ppss' to be correct and it seems to be OK
+  ;; to use it here despite initial worries.)  We also have to sort
+  ;; out a possible prefix -- well, we don't _have_ to, but I think it
+  ;; should be treated as part of the string.
+
+  ;; Test cases:
+  ;;  ur"""ar""" x='"' # """
+  ;; x = ''' """ ' a
+  ;; '''
+  ;; x '"""' x """ \"""" x
+  ;; Fixme:  """""" goes wrong (due to syntax-ppss not getting the string
+  ;; fence context).
+  (save-excursion
+    (goto-char (match-beginning 0))
+    (cond
+     ;; Consider property for the last char if in a fenced string.
+     ((= n 3)
+      (let ((syntax (syntax-ppss)))
+	(when (eq t (nth 3 syntax))	; after unclosed fence
+	  (goto-char (nth 8 syntax))	; fence position
+	  (skip-chars-forward "uUrR")	; skip any prefix
+	  ;; Is it a matching sequence?
+	  (if (eq (char-after) (char-after (match-beginning 2)))
+	      (eval-when-compile (string-to-syntax "|"))))))
+     ;; Consider property for initial char, accounting for prefixes.
+     ((or (and (= n 2)			; leading quote (not prefix)
+	       (= (match-beginning 1) (match-end 1))) ; prefix is null
+	  (and (= n 1)			; prefix
+	       (/= (match-beginning 1) (match-end 1)))) ; non-empty
+      (unless (nth 3 (syntax-ppss))
+        (eval-when-compile (string-to-syntax "|"))))
+     ;; Otherwise (we're in a non-matching string) the property is
+     ;; nil, which is OK.
+     )))
+
+
 (put 'python-mode 'font-lock-defaults '(python-font-lock-keywords))
 
 ;; have to bind py-file-queue before installing the kill-emacs-hook
@@ -1189,7 +1246,10 @@
   (setq major-mode              'python-mode
 	mode-name               "Python"
 	local-abbrev-table      python-mode-abbrev-table
-	font-lock-defaults      '(python-font-lock-keywords)
+    font-lock-defaults    '(python-font-lock-keywords nil nil nil nil
+                            (font-lock-syntactic-keywords
+                             . python-font-lock-syntactic-keywords))
+
 	paragraph-separate      "^[ \t]*$"
 	paragraph-start         "^[ \t]*$"
 	require-final-newline   t


-- 
Regards,
Rob



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